State symbols

Redox half-reactions are often written for brevity as, for example, Li Li. with the state symbols omitted. The electrode... 

A number of redox potentials for ion-ion systems are given in Fable 4.3 here again, state symbols are often omitted. 

In the sodium atom pairs of 3/2 states result from the promotion of the 3s valence electron to any np orbital with n > 2. It is convenient to label the states with this value of n, as n P 1/2 and n f 3/2, the n label being helpful for states that arise when only one electron is promoted and the unpromoted electrons are either in filled orbitals or in an x orbital. The n label can be used, therefore, for hydrogen, the alkali metals, helium and the alkaline earths. In other atoms it is usual to precede the state symbols by the configuration of the electrons in unfilled orbitals, as in the 2p3p state of carbon. 

A chemical equation typically also shows the physical state of each reactant and product by using a state symbol ... 

There are four H atoms and two O atoms on each side of the arrow. At this stage, we insert the state symbols ... 

A note on good practice The chemical equations for elementary reaction steps are written without the state symbols. They differ from the overall chemical equation, which summarizes bulk behavior, because they show how individual atoms and molecules take part in the reaction,. We do not use stoichiometric coefficients for elementary reactions. Instead, to emphasize that we are depicting individual molecules, we write the formula as many times as required. 

The most common states of a pure substance are solid, liquid, or gas (vapor), state property See state function. state symbol A symbol (abbreviation) denoting the state of a species. Examples s (solid) I (liquid) g (gas) aq (aqueous solution), statistical entropy The entropy calculated from statistical thermodynamics S = k In W. statistical thermodynamics The interpretation of the laws of thermodynamics in terms of the behavior of large numbers of atoms and molecules, steady-state approximation The assumption that the net rate of formation of reaction intermediates is 0. Stefan-Boltzmann law The total intensity of radiation emitted by a heated black body is proportional to the fourth power of the absolute temperature, stereoisomers Isomers in which atoms have the same partners arranged differently in space, stereoregular polymer A polymer in which each unit or pair of repeating units has the same relative orientation, steric factor (P) An empirical factor that takes into account the steric requirement of a reaction, steric requirement A constraint on an elementary reaction in which the successful collision of two molecules depends on their relative orientation. 

Although not conunented on by Smith and Metz (1996), the drawings iuFigs. 3.8 and 3.9 might have revealed that some of the students were not entirely famihar with the state symbols. The question and the equation stated explicitly that the reaction takes place in aqueous solution. Nevertheless, these drawings did not make ary reference to the fact that the reaction or the chemical species are in an aqueous medium. 

Notice that ID wn+1 can differ in at most three positions from ID w state, symbol scanned and symbol left of scanned symbol if the move is left). 

For soluble ionic compounds, ions are written separately using the state symbol (aq). 

Redox half-reactions are often written for brevity as, for example, Li+ + e - Li. with the state symbols omitted. The electrode system represented by the half-reaction may also be written as Li+ /Li. The standard redox potentials for ion-ion redox systems can be determined by setting up the relevant half-cell and measuring the potential at 298 K relative to a standard hydrogen electrode. For example, the standard redox potential for the half-reactions... 

As already discussed, the interaction of electromagnetic radiation with matter leads to absorption only if a dipole moment is created as a result of such interaction. During the process of emission the dipole is destroyed. This may be stated symbolically as d /dt is positive and d fdt 0. 

The number of unpaired spins for an ion in its ground state is obviously determined by the multiplicity, 2 -fl, of that state and vice versa. The multiplicity is written in the upper left hand comer of the symbol for the state. Thus the ground state symbol can be read off from the appropriate correlation diagram and, if spin-only conditions apply, the effective magnetic moment can be immediately determined. 

Six electrons are transferred in the equation for this redox reaction. Now add the two half-reactions simplify the equation by canceling species that appear on both sides (in this case, electrons, HzO, and OH-) and attach state symbols. We obtain the following fully balanced equation ... 

Often instead of using state designations molecular orbital terminology is used to describe a transition (vide infra). To be consistent with the accepted convention for state symbols the higher MO should be written first (15). Thus the absorption of molecular hydrogen at 1100 A., -... 

Mulliken State Symbols.—In this classification, states are represented by different capital letters, e.g., N, Q, V, T, R, etc. (17), where N (normal) stands for the, ground state and F, for example, stands for an excited state having large ionic character. Thus the absorption of hydrogen at 1100 A.,... 

Transitions, particularly in simple molecules, are also expressed in terms of all the molecular orbitals involved and the state symbols are also included. For example the 1100 A., V—N transition in the hydrogen molecule may be written (15)... 

Balanced equations often include the physical state symbols ... 

When we replace the words with symbols for the reactants and the products and include their physical state symbols, we obtain ... 

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